This renewal grant application, proceeding from our recent findings with Type I diabetes has three related yet independent foci: 1) Using more valid and reliable technology not available during our initial research, the proposal will continue to test the exent to which individuals can accurately discriminate BG levels. Going further, the proposed studies investigate physiological variables, such as the ability to counterregulate, which may be responsible for individual differences in ability to perceive BG. Efforts will be made to assess behavioral and metabolic effects of one's actual and/or believed ability to perceive BG symptoms. Finally, the effectiveness of two discrimination training techniques to improve BG perception and symptom beliefs will be tested. 2)\Our experience indicates that some individual's metabolic status is very sensitive to psychological stress. The present studies will attempt to identify the mechanisms of this stress-BG relationship, examining the mediating role of physiological factors, such as the ability to counterregulate and plasma insulin levels, and psychological factors, such as coping ability. The clinical significance of stress in the natural environment and a method for reducing its impact will be tested. 3) The initial research focus has been extended beyond subjective symptoms to include how BG fluctutions impact cognitive/motor functioning. Not only can identifiction of BG-relevant dysfunction be used to cue patients as to their BG level, but better understanding of this phenomena can facilitate human engineering of diabetic apparatus. Over five years, 80 Ss will be assessed in terms of 1) ability to identify BG-relevant cues and BG level 2) therapeutic adherence and 3) various diabetic-relevant psychological variables. They will then be hospitalized to assess BG response to psychologicl and hormonal stressors and ability to counterregulate during insulin infusion. Ss will then be assigned to one of three treatment groups. The BG Discrimination Group will evaluate the extent to which two different techniques will improve Ss' ability to perceive BG level and the behavioral and metabolic impact of this improvement. The Prospective Stress Group will evaluate stress-BG relationships in the natural environment and individual differences in vulnerability to stress. The Pump Group will be used to assess the effects of steady insulin infusion on BG reactivity to stress.